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Digital Processing at Analog Price

Broadcast Warehouse's DSP-X Processor Is Lightweight, Clean and Made for 'Tweakers'

Broadcast Warehouse’s DSP-X Processor Is Lightweight, Clean and Made for ‘Tweakers’

With digital signal processor chips becoming ever more powerful and less expensive, it doesn’t take a genius to predict that broadcast audio processing will move almost entirely into the digital domain over the next decade. When it’s done right, digital processing can sound amazingly good, subtly shaping your sound in ways that analog processors can’t even attempt.
Product CapsuleTHUMBS UP:

Lightweight, small

Little heat

Attractive blue LED display

Excellent remote-control capabilities



The documentation needs attention

PRICE: $3,600

CONTACT: Broadcasters General Store in Florida at (352) 368-5092 or visit
Not everyone does it right. The devil is in the details – or more accurately, the algorithms used to control the audio levels on the way to your exciter or digital encoder.

The DSP-X processor from UK-based Broadcast Warehouse takes advantage of the latest DSP chips to offer expert processing, including simultaneous and separately limited digital and analog outputs, for much less than competitive digital processors.

Given that we use digital processing at all of our stations nowadays, I was anxious to test the DSP-X.

Under the hood

The DSP-X is surprisingly small and light. It fits into a single rack space and weighs about 2 lbs. If you’ve ever thrown your back out lifting an old Optimod, you’ll love the DSP-X; the AC cord that I used was heavier than the unit.

The front-panel controls consist of a single multipurpose knob for adjusting parameters and three small pushbuttons that are used primarily for menu navigation. There are LED meters for the multi-band processing, input and output levels. There also is an excellent remote control interface; more on that in a moment.

On the rear panel are RS-232 and NET/LAN remote control ports, as well as an additional DB-9 connector for remote switching. For convenience, there is one more RS-232 port on the front, useful if you don’t feel like digging into a rack at the transmitter site.

The input and output jacks for audio are XLR types for analog and AES/EBU digital. BNC connectors provide pilot and composite output; a third BNC allows you to inject SCA material. An AES/EBU sync input is provided.

Under the hood, the DSP-X has multiple 24-bit digital processors, 128 times oversampling, two stages of four-band AGC and two limiter sections. One limiter is a traditional “brick wall” type for the FM stereo composite generator; the other is a look-ahead type with different dynamics.

The FM stereo generator is hardwired to the brick wall stage, but you can select either limiter to drive the XLR outputs. Broadcast Warehouse recommends that the look-ahead output be used with digital streaming. The digital and analog outputs can each be optimized for digital streaming or on-air broadcasting, and can be used simultaneously.

I had tried this unit earlier with Version 1 of the software. After I began testing, Version 2 became available and I downloaded it. Upgrading the software can be done from any computer with a decent communications program, such as Windows’ own Hyperterminal. It takes about five minutes.

For my tests, I connected the DSP-X to an Inovonics modulation monitor and used headphones to monitor both the direct audio outputs and the output from the Inovonics unit. My input source was a Denon CD player. I also listened through JBL studio monitors for some tests. Armed with several CDs ranging from classical to metal, I started playing and listening.

The front panel control functions aren’t difficult to use. I quickly figured out how to load presets, change parameters and adjust the input and output levels. But where this system really shines is when you use the Windows-based remote interface, new for Version 2 of the software. The DSP-X system gives you more control over your sound than any comparable processor I’ve ever tried, and the Windows-based interface lets you do it all in a point-and-click graphical environment.

The screen shot on this page shows just one of many neat features: you can “solo” each of the four bands, listening to each separately, to precisely fine-tune your mix.


Now for the part you’ve been waiting for. How does it sound? In five words, however you want it to.

Generally speaking, the DSP-X is very clean, with tight bass and clear highs. To get the exact sound you want, the DSP-X comes with several presets that can be used to get it working out of the box; if you like, you can then tweak these as desired.

With Version 2’s Windows-based interface, you can easily sit down and fiddle until you get just the sound you want. The remote control program can use either RS-232 or TCP/IP. I recommend the latter. With the TCP/IP interface, you can adjust the unit from anywhere; all you need is an Internet connection and the Version 2 software installed on your PC.

This processor is worth considerably more than the asking price. It sounds good, is as flexible as a hot rubber band and can drive digital and analog outputs simultaneously, each with its own limiter optimized for that use. This is perfect for a station that streams audio onto the Web; there’s no need to buy a separate processor.

The user’s manual is adequate, but could use a little more work, such as better illustrations and walk-throughs for the less technically inclined. However, the team at Broadcast Warehouse was responsive to questions via email.

If you’re a tweaker, you’ll find a lot to love with this unit. The ability to individually tweak each of the four bands, and even better, to “solo” each band so that you can listen for artifacts, is excellent. This processor has features I haven’t seen in processors costing much more, but there’s no way I can list them all here.

This doesn’t mean you have to be a gadget freak or a hacker to use the DSP-X. The provided default presets will work for most situations. Simply install the DSP-X and choose the one that best suits your programming.